Niveums silver leaf, nutrient deficiency or?

[IvoPhal]

I have 2 pots 12 cm with 3 niveums. They are potted in bark, perlite and quarts sand. I used in thei culture since September kelpak and akerne feet, calamag, oyster shells sand and some seaweed. All are derived from 1 pot when I bought it.
The 1 one is in good shape planted alone(see pics) the other one is in bud with 2 yellow leaves ( that’s my concern) and the other one is not growing.
Why they react so differently? They are treated the same way, light, temp at the windowsill? Is there some nutrient deficiency or I have to see roots ….

 

[big923cattleya]

Are those mealybugs down in the growth with the bud? It sure looks like it but from your images I can not be sure.
This group of orchids, the Brachypetalums are fairly slow growers. They live in the leaf litter one top of limestone outcroppings. They never really like to dry out and mine do not seem to enjoy being too wet either. Niveum, concolor, godefroyae, bellatulum, leucochilum, etc. all feature dark green leaves with silver markings or tessellations.
They are small plants, I would be careful about applying too much fertilizer. I my experience under lights, they prefer subdued light and both concolor and bellatulum are the easiest for me to grow.

 

[IvoPhal]

No, it’s not mealy bugs, oysters shell sand but a messy application
Actually the question is that one plant potted in 2 pots, the same media , fertiliser msu/akerne 100 N ppm weekly is growing differently.
1. Is growing with strong leaves
2. Is blooming but the the leaves are yellowing
3. Plant it’s not growing

 

[Stone]

The first leaves yellowing when the plant is coming into flower is usually potassium and/or nitrogen being removed to enable flowering to continue if these elements are deficient in those leaves. Given that niveum normally flowers in the spring, it should be able to flower without any fertilizer being applied over winter and still hold the old leaves. But note that it must have good roots during the previous growing season to be able to accumulate these elements well. Niveum is a completely tropical plant and prefers minimum overnight temperatures no lower than 18C during rest or at the very least 15C if kept almost completely dry. When the leaves are yellowing and the plant is blooming it will most certainly not do anything for months after blooming is over as it will completely exhausted. They do not like repotting either.

 

[IvoPhal]

Thank you, I appreciate your input. I understand completely what you mean.

 

[Tom-DE]

For windowsill growers--If you feed your plants, even if just only once a month, nutrient deficiency is uncommon IMO. This time of the year(winter), most of the Brachypetalum will not do much anyway. Also, the roots are sensitive to salt accumulation. The excessive yellow leaves or immature dying always trace back to the salt problem at the roots for this group of Paph. I will check if the mix is still fresh with good drainage, and also check the root condition. Flush the pot often...

 

[BrucherT]

When were these plants last repotted? To me, the mix is looking old. I disagree about these not liking to be repotted. I find the respond to repotting like all Paphiopedilum and that old, rotting/breaking-down mix is a problem. It’s self-fulfilling, too, that if you wait too long to repot, they will already be suffering and then of course they’ll struggle initially when they do get repotted.

 

[Tom-DE]

but how often is it? I don't think it is necessary to repot Paphs often either. You may repot seedlings more often but for mature plants, It is not necessary, unless you have bad water or bad culture practice.
I repot my mature plants every 3-4 years, in generral.

 

[Stone]

The excessive yellow leaves or immature dying always trace back to the salt problem at the roots for this group of Paph.

What is the mechanism by which this happens Tom? I mean, why would the old leaves die before the others due to high salinity?

 

[Tom-DE]

Mike, old mix and salt buildup cause root loss... plants are unable to have sufficient water and nutrient intake. That will cause yellow leaves, black tips, and early die-off, wrinkles on the leaves as well.

 

[IvoPhal]

So, I repotted them in September 2024. I measured Ph and salinity in ppm and CHC mix, that they were planted from seller was 1400 ppm. I decided to repot the whole clump. So, I divided in two 12 cm pots with ready mix for paphs, I added coral/quartz sand, oyster shell sand and kelpak. 1 mounth in a bag, than kelpak each month, my water is tap water , pure one I added sometimes citric acid to reach 6 ph. I flushed substrate one or two times with flush hydroponic TA. I measured ph of substrate it was around 7 ph. I feed weekly with msu/akerne 100 N ppm. Even less.
The strange for me is that one niveum is doing very well , the other pot the plant is budding and the other is showing little progress (see pics)
What can be my beginner mistake…feeding to much, but 1 plant is ok, error during repotting but there’s some progress and budding….

 

[Stone]

Does not seem like a salinity problem to me but I would suggest that repotting in September in the northern hemisphere is not so good.

 

[Ray]

@Stone, and anyone else that would like to chime in, what are your thoughts on this speculation?

As potting media age, the overall chemistry changes from that of fresh media with mineral buildup and pH change. Ignoring for a moment the directly toxic effects, might those changes stifle the compensatory secretions associated with nutrient ion uptake, leading to nutrient deficiencies?

 

[IvoPhal]

Yep, actually it was pretty hot and October too 20-25 degrees Celsius.
Thank you for suggesting spring and summer to be more suitable for reporting. Not to stress the paphs, I mean.

 

[IvoPhal]

So, Ray, everything is ok with my niveums? That’s a natural way these plants to grow? I mean the older leaves are yellowing and the force of the plant is moving towards the new leaves, buds?
For the first time I have niveums and that’s the reason why I’m worried about them.

 

[Brabantia]

For me 100 ppm N Akerne /MSU per week is to hight . Check your conductivity of your solution and you will be surprised.
Akerne recommand 65 ppm N per week and this is already to hight for this paphiopedilum family. 40 to 50 ppm N per week is enought. They are slow grower !.

 

[IvoPhal]

Merci, monsieur.
Like a plan I will stopping fert for 2 weeks and will flush the media, and watering them like winter Phalaenopsis.
Probably with S/H 100 N ppm should be ok with niveums, I’m still thinking.

 

[Ray]

Merci, monsieur.
Like a plan I will stopping fert for 2 weeks and will flush the media, and watering them like winter Phalaenopsis.
Probably with S/H 100 N ppm should be ok with niveums, I’m still thinking.

No. Just the opposite is true, due to exposure time.

Think about a bare-root vanda in a basket - it only gets fed for the short period of time the velamen gets saturated during watering. After that, nothing.

Now move up the scale to a plant in a pot of bark - it gets fed for that same “while being applied” time and for a short while after, until the solution in the bark nearest the roots dries.

Now go to S/H, where the exposure to the nutrient solution is constant.

If the same solution was applied to all three, the vanda would get the least and the plant in S/H would get the most. As we’re trying to control the mass of nutrients absorbed, the solution applied to the S/H plant should be significantly more diluted.

 

[Stone]

@Stone, and anyone else that would like to chime in, what are your thoughts on this speculation?

As potting media age, the overall chemistry changes from that of fresh media with mineral buildup and pH change. Ignoring for a moment the directly toxic effects, might those changes stifle the compensatory secretions associated with nutrient ion uptake, leading to nutrient deficiencies?

It's definitely possible but if there is good root action throughout the medium that is unlikely. This is evidenced by the fact that Dr Tanaka has given us examples of a paph bellatulum in the same pot for 10 years and it still retains it's old leaves. It seems vigorous root action keeps these changes you mention to a minimum. All the old books mention it. They used to call it ''souring'' but I think it is more than mere pH changes. There is probably some kind of biological change as well. Probably involving fungi. One of the remedies was/is submersion in a solution of calcium hydroxide.

 

[Stone]

I mean the older leaves are yellowing and the force of the plant is moving towards the new leaves, buds?

We can only do our best but remember that ideally these plants should hold their older leaves for years. This is not a niveum but a good example of a happy brachy with lots of old leaves in good condition. I thought it was interesting that it is growing on a tree too. It is also show us that the only carbonate needed is enough to stop the mix becoming too acidic and that's all. Chunks of limestone - not necessary.